1. The document discusses various techniques for mechanical thrombectomy in acute stroke, including thrombectomy devices, thromboaspiration, and thrombolysis. 2. It summarizes key trials investigating mechanical thrombectomy including DAWN, DEFUSE 3, and a basilar artery occlusion trial. The DAWN and DEFUSE 3 trials showed improved outcomes with thrombectomy plus standard care compared to standard care alone for certain patients. 3. The document outlines considerations for implementing a mechanical thrombectomy program, including patient selection criteria, imaging guidance, procedural timelines, equipment needs, and cost estimates.

1. Mechanical
Thrombectomy in
Acute Stroke
Presented by : Dr Sumeet Singh
SR NEUROLOGY
GMC Kota

3. IV TPA - LIMITATIONS
 ICA and M1 occlusions have lower rate of recanalization than M2–M4
occlusions. •
 52% with NIHSS <10 will reach NIHSS of 1 after IV tPA, but only 8% with
NIHSS >20 •
 30% of MCA occlusions recanalize with IV tPA only within 2 hours
 ICA occlusions recanalize only at 1/3 of the rate of MCA occlusions.

4. Endovascular management
 Sussman and Fitch described the IA treatment of acute carotid occlusion
with fibrinolysin injection in 1958.
 Late1990’s experienced exponential progress and development.
 Recent advances in endovascular techniques have increased the
therapeutic window of r-TPA administration.
 The newer IA devices for clot retrieval and vessel recanalization has
revolutionized the neuroendovascular management of acute ischemic
stroke.

5. CT PERFUSION SCANS
 CT perfusion scans “ salvageable” tissue.
 Perfusion scan demonstrates the penumbra lesion
volume or mean transit time which is essential for
determining outcomes.

6. Late revascularisation of AIS is based on advanced
imaging or mismatch

8. Angiographic evaluation
 To see for ischemic etiology and initiation of treatment.
 Examination of the cerebrovascular anatomy begins with the aortic arch.
 Based on the patient symptomatology and pre-procedure imaging,
selective catheterization of the carotid or vertebrobasilar circulation
supplying the affected territory is performed
 Attention is paid to the extracranial collateral circulation, the
leptomeningeal anatomy, the circle of Willis, and overall global cerebral
perfusion.
 Grade of angiographic collaterals is a decisive factor for the degree of
reperfusion and clinical improvement

9.  Intra-arterial mechanical thrombolysis Broadly categorized into the
following categories:
1. Thrombectomy
2. Thromboaspiration
3. Thrombus disruption
4. Augmented fibrinolysis
5. Thrombus entrapment.

10. Endovascular thrombectomy
 Devices under this category apply a constant force to the clot material at
its proximal or distal end and facilitate clot removal. Proximal end forces
are applied through grasp-like attachments, whereas distal end forces are
applied via basket-like devices.
 The advantage of these devices is their decreased association with
embolic material since there is no attempt for mechanical clot disruption.
 Some of the most widely used examples are the Merci retriever
(Concentric Medical, Mountain View, California), the Neuronet device
(Guidant, Santa Clara, California), the Phenox clot retriever (Phenox,
Bochum, Germany), the Catch thrombectomy device (Balt Extrusion,
Montmorency, France), and the Alligator retrieval device (Chestnut
Medical Technologies, Menlo Park, California).

12. Endovascular thromboaspiration
 The functioning mechanism in this category utilizes an aspiration
technique, which is suited for fresh non-adhesive clots.
 These devices also have the advantage of fewer embolic material and
decreased vasospasm.
 Some examples in this category are the Penumbra system (Penumbra,
Alameda, California) and the AngioJet system (Possis Medical,
Minneapolis, Minnesota).
 The Penumbra stroke system (Penumbra, Inc, Alameda, CA) is increasingly
popular and uses 2 types of devices to remove occlusive
thromboembolus in acute ischemic stroke.

14. MECHANICAL THROMBUS DISRUPTION -
PTA - Microwire/microcatheter fragmentation

15. Augmented fibrinolysis
 These devices, such as the MicroLysUS infusion catheter (EKOS, Bothell,
Washington), utilize a sonographic micro-tip to facilitate thrombolysis through
ultrasonic vibration.
 The clot removal is augmented without any additional fragment embolization to
the distal circulation.

16. Thrombus entrapment
• The underlying mechanism of
these devices utilizes a stent to
recanalize the occluded vessel and
therefore trap the clot between the
stent and vessel wall.
• Stents can be deployed via a
balloon mechanism or could be
self- expandable. The latter are
becoming increasingly popular due
to their flexibility and ease of
navigation

17. Solitaire & Trevo “Stentriever
 Self-expandable •
 Retrievable •
 Dual functionality:
1. Acts as a temporary intracranial bypass providing immediate flow restoration
through the thrombus •
2. Acts as a clot retriever, trapping thrombus into its cells allowing for clot
removal •

20. Mechanical thrombectomy
Acute ischemic stroke
CT Angiography s/o Large artery occlusion
<6hours since onset >6hours since onset

21. DAWN TRIAL
 Diffusion-weighted imaging or computerized tomography perfusion
assessment with clinical mismatch in the triage of wake up and late
presenting strokes undergoing neurointervention with Trevo (DAWN)
trial methods

22. Study design
Study Type : Interventional (Clinical Trial)
Actual Enrollment : 206 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Diffusion Weighted Imaging (DWI) or Computerized Tomography Perfusion
(CTP) Assessment With Clinical Mismatch in the Triage of Wake Up and Late
Presenting Strokes Undergoing Neurointervention (DAWN)
Study Start Date : July 2014
Actual Primary
Completion Date :
May 15, 2017
Actual Study
Completion Date :
May 15, 2017

23. General inclusion criteria
1. Clinical signs and symptoms consistent with the diagnosis of an acute
ischemic stroke, and subject belongs to one of the following subgroups: a.
Subject has failed IV t-PA therapy (defined as a confirmed persistent
occlusion 60 min after administration) b. Subject is contraindicated for IV t-
PA administration
2. Age ≥18
3. Baseline NIHSS ≥10
4. Subject can be randomized between with 6 to 24 h after time last known
well
5. No significant pre-stroke disability (pre-stroke mRS must be 0 or 1)
6. Anticipated life expectancy of at least 6 months
7. Subject willing/able to return for protocol required follow-up visits
8. Subject or subject’s legally authorized representative (LAR) has signed the
study informed consent form

24. Imaging inclusion criteria
 1. <1/3 MCA territory involved, as evidenced by CT or MRI
 2. Occlusion of the intracranial ICA and/or MCA- M1 as evidenced by
MRA or CTA
 3. Clinical imaging mismatch (CIM) defined as one of the following on
MR-DWI or CTP-rCBF maps:
a. ≥ 80 y/o, NIHSS ≥10 + core <21 mL
b. < 80 y/o, NIHSS ≥10 + core <31 mL
c. < 80 y/o, NIHSS ≥20 + core <51 mL

26. Efficacy outcomes

27. Safety outcomes

28. Results
 A total of 206 patients were enrolled; 107 were assigned to the thrombectomy
group and 99 to the control group.
 At 31 months, enrollment in the trial was stopped because of the results of a
prespecified interim analysis.
 The mean score on the utility-weight-ed modified Rankin scale at 90 days was
5.5 in the thrombectomy group as compared with 3.4 in the control group and
the rate of functional independence at 90 days was 49% in the thrombectomy
group as compared with 13% in the control.
 The rate of symptomatic intracranial hemorrhage did not differ significantly
between the two (6% in the thrombectomy group and 3% in the control group
nor did 90-day mortality (19% and 18%).

29. Conclusion
 Among patients with acute stroke who had last been known to be well 6 to 24
hours earlier and who had a mismatch between clinical deficit and infarct,
outcomes for disability at 90 days were better with thrombectomy plus
standard care than with standard care alone.

30. DEFUSE 3 TRIAL
 A multicenter randomized controlled trial of endovascular therapy
following imaging evaluation for ischemic stroke (DEFUSE 3)

31. Study design
Study Type : Interventional (Clinical Trial)
Actual Enrollment : 182 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3
Study Start Date : April 2016
Actual Primary
Completion Date :
August 23, 2017
Actual Study
Completion Date :
August 23, 2017

32. Clinical inclusion criteria
 1. Signs and symptoms consistent with the diagnosis of an acute anterior
circulation ischemic stroke
 2. Age 18–90 years
 3. Baseline NIHSS score ≥6
 4. Endovascular treatment can be initiated (femoral puncture) between 6
and 16 h of stroke onset. Stroke onset is defined as the time the patient
was last known to be at their neurologic baseline (wake-up strokes are
eligible if they meet the above time limits)
 5. Modified Rankin Scale ≤2 prior to qualifying stroke
 6. Patient/Legally authorized representative has signed the informed
consent form

33. Neuroimaging inclusion criteria
 1. ICA or MCA-M1 occlusion (carotid occlusions can be cervical or
intracranial; with or without tandem MCA lesions) by MRA or CTA
 2. Target Mismatch Profile on CT perfusion or MRI (ischemic core volume
is <70 ml, mismatch ratio is ≥1.8 and mismatch volume is ≥15 ml)

34. RAPID mismatch map.
The RAPID mismatch summary map allows
investigators to quickly, accurately, and easily
determine if the patient meets the imaging criteria
for enrollment. The case shown here meets the Target
Mismatch criteria: core volume is<70 ml, mismatch
ratio is ≥1.8 and mismatch volume is ≥15 ml.

35. A baseline CT perfusion scan that was obtained with the use of RAPID software shows
a region of severely reduced cerebral blood flow (<30% of that in normal tissue),
which represents the early infarct (ischemic core), of 23 ml (pink) and a region of
perfusion delay of more than 6 seconds, which represents hypoperfused tissue, of 128
ml (green). Volume of Ischemic Core, 23 ml Volume of Perfusion Lesion, 128 ml
Mismatch volume, 105 ml Mismatch ratio

36. Results
 The trial was conducted at 38 U.S. centers and terminated early for efficacy
after182 patients had undergone randomization (92 to the endovascular-
therapy group and 90 to the medical-therapy group).
 Endovascular therapy plus medical therapy as compared with medical therapy
alone, was associated with a favorable shift in the distribution of functional
outcomes on the modified Rankin scale at 90 days and a higher percentage of
patients who were function-ally independent, defined as a score on the
modified Rankin scale of 0 to 2 (45%vs. 17%).
 The 90-day mortality rate was 14% in the endovascular-therapy group and 26%
in the medical-therapy group and there was no significant between-group
difference in the frequency of symptomatic intracranial hemorrhage (7% and
4% respectively) or of serious adverse events

37. Conclusion
 Endovascular thrombectomy for ischemic stroke 6 to 16 hours after a patient
was last known to be well plus standard medical therapy resulted in better
functional outcomes than standard medical therapy alone among patients
with proximal middle-cerebral-artery or internal-carotid-artery occlusion and
a region of tissue that was ischemic but not yet infarcted.

38. Trial of Endovascular Treatment of Acute
Basilar-Artery Occlusion

39. Study design
Study Type : Interventional (Clinical Trial)
Actual Enrollment : 340 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Endovascular Treatment for Acute Basilar Artery Occlusion -
a Multicenter Randomized Clinical Trial
Actual Study Start
Date :
February 21, 2021
Actual Primary
Completion Date :
January 3, 2022
Actual Study
Completion Date :
April 3, 2022

40. Results
 one third of whom received intravenous thrombolysis, endovascular
thrombectomy within 12 hours after stroke onset led to better functional
outcomes at 90 days than best medical care but was associated with
procedural complications

41. Advantages of intra-arterial mechanical
thrombolysis
 The mechanical disruption of the arterial clot has several advantages in
management of acute stroke.
1. First, it increases the working surface area for thrombolytic agents thereby
enhancing their efficacy.
2. Even partial removal of clot via retrieval or thromboaspiration techniques
lessens the concentration of IA agent required to dissolve the remainder
pieces and risk of ICH is reduced.
3. Provides patients with contraindications to anticoagulation with a reasonable
alternative to endovascular therapy.

42. Risk of Mechanical thrombectomy
 The use of mechanical thrombolysis is associated with several associated
risks.
1. The endovascular trauma to the blood vessel could cause endothelial
damage, permanent vascular injury, and ultimately vessel rupture, especially
in old friable vessels.
2. The technical skills needed for the endovascular navigation of such devices,
especially through severely occluded segments, are substantial, and require
rigorous training.
3. Finally, the dislodged clot material could become an embolic source,
exposing the already compromised distal circulation to additional ischemic
risks.

43. PLAN OF ACTION AT OUR SETUP
 We plan to include patients with acute ischemic stroke who have
1. Age between 18-80
2. NIHSS>= 6
3. Present between 6 to 24 hours of insult.

44. 0 hrs
3 hrs
6 hrs
9 hrs
12 hrs
Routine investigations
CT angiography/ MR
Angiography
Perfusion scans DWI flair
mismatch
Alarm and inform the team
of
Interventional neurologist
Neurosurgeon
Anesthesiologist
Nursing staff of cathlab
Prepare the patient for
procedure
Check instruments
Procedure time
It should be done between
6 and 24 hours of onset of
symptoms
Post
procedure
care

45. Requirement list for Mechanical
thrombectomy
 Revascularization device for mechanical thrombectomy US FDA approved
 Thrombus suction catheter for clot retrieval from carotids and vertebral
artery US FDA approved
 Selective infusion microcatheter for deploying intra cranial device
 Special micro guiding wire with torque device for use with microcatheter.

46. Package code for mechanical
thrombectomy
 Package code- for intracranial thrombolysis/ clot retrieval -28490000013 with
cost value of 152000.

47. References
 New England journal of Medicine
 Continuum journal of neurology
 Bradley 8th edition
 1. Berkhemer OA, Fransen PSS, BeumerD, et al. A randomized trial of
intraarterial treatment for acute ischemic stroke N England J Med
2015;372:11-20.
 13. Stryker. Welcome to the DAWN trial campus
(http://dawntrial.trainingcampus.net).

48. Thank you